I have some problems with nvsound and nvmixer with any version of the nforce drivers (tried up to the newest 1.0-0310): I have an nforce3 chipset audio card (on a laptop) and with nvmixer I have no access to the PCM (or wave, or whatever) volume control, nor to the headphones output volume control. It is a problem because the driver doesn't recognize when the headphones are plugged, and I cannot thus separately mute the external speaker and enable the heaphones alone. With older versions of ALSA (snd-intel8x0 kernel module) the jack plug was not sensed as well, but I had separate control over each input-output channel: I could mute speakers and/or headphones (note: their name were correctly recognized, so that speakers was "master" and headphones was "headphones", not some strange "line#" or the like) and set separate output level for each one. With newer alsa drivers (from the ones in stock kernel 2.6.12, if I'm not wrong), I also get in alsamixer the swich for "hp jack sense" which works perfectly, muting the speakers when hp are plugged in. But with nvmixer I can only change the master volume (wich works on the hp output level as well), but it doesn't mute the speaker in any way. I can post some screenshots of the mixers if you think they're useful.

I'll also post a bug-report as soon as I have some time to reboot the machine.